1. Field of Invention
Not applicable.
2. Description of Related Art
The ability to detect the unauthorized transportation of radioactive materials would be facilitated by a large-scale network of radiation sensors. However, the installation of such a network of radiation sensors would be costly and delay the readiness of the system.
Radiation sensing networks are being developed in Europe in case of a nuclear power-plant accident. For example, the Real-time On-line Decision Support (RODOS) system for off-site emergency management in Europe is being planned to provide consistent and comprehensive information on present and future radiological situations, the extent, benefits and drawbacks of emergency actions and countermeasures, and methodological support for making decisions on emergency response strategies. RODOS includes geographical, meteorological and radiation propagation detection modules; it also serves as a data accumulation point for radiological and atmospheric monitoring networks. Radiation sensing data provided by networked detectors would complement and enrich the radiation database like RODOS available to security authorities and disaster recovery agencies.
The ability to detect the unauthorized transportation of radioactive materials over a wide area is pressing due to the break-up of countries having nuclear weapons and nuclear reactors. Radioisotope smuggling and black market sales of radioactive material has increased substantially in the recent past. A General Accounting Office report documents some of the International Atomic Energy Agency's (IAEA) 181 confirmed cases of illegal sales of nuclear material since 1992. Twenty of these incidents involved the transfer or attempted transfer of nuclear weapons useable material, namely Pu-239 and 20%-90% Highly Enriched Uranium (HEU). Although the most ominous risk from rogue radiological material is related to HEU's use in the construction of a nuclear bomb, HEU could also be used as the raw material for a Radiological Dispersal Device or “dirty bomb”. Indeed, any radioisotope can be used in the construction of a dirty bomb. However, some radioisotopes, for example Cs-137, Sr-90, or Co-60 are more dangerous than others for this application. For example, U-235, due to its comparatively low level of gamma ray activity, is not nearly as dangerous as a comparable mass of Co-60. Dirty bombs would be economically devastating to a region due to the high expense for decontamination, clean up, and economic loss should one be detonated.
Radioactive material dispersed via the detonation of a conventional explosive would be economically devastating to the region affected. Access to non-weapons-usable nuclear material is typically easier than to HEU or Pu-239, magnifying the dirty bomb threat arising from non-weapons-usable materials. This threat is heightened by the fact that nuclear contraband is typically smuggled in quantities that rarely exceed one kilogram and that nearly all of the smuggling cases were detected due to police investigations. The clean-up costs from even this small amount of radioactive material could be tremendous. It is better to detect the illegal transport of radiological materials and interdict it at an early stage.
A need exists for detecting the illegal transportation of radioactive material. There is a need for a cost effective and wide spread network of sensors that can detect radioactive material, identify its location, and provide an alert when this type of material is detected.